The present invention relates to methods and compositions for the treatment of leukemia, lymphoma, and certain other cancers.
More specifically, the present invention relates to the novel uses of arsenic trioxide and an organic arsenic compound for treating acute leukemia and chronic leukemia.
Cancer is characterized primarily by an increase in the number of abnormal cells derived from a given normal tissue, invasion of adjacent tissues by these abnormal cells, and lymphatic or blood-borne spread of malignant cells to regional lymph nodes and to distant sites (metastasis). Clinical data and molecular biologic studies indicate that cancer is a multistep process that begins with minor preneoplastic changes, which may under certain conditions progress to neoplasia.
Pre-malignant abnormal cell growth as exemplified by hyperplasia, metaplasia, and dysplasia (for review of such abnormal growth conditions, see Robbins and Angell, 1976, Basic Pathology, 2d Ed., W. B. Saunders Co., Philadelphia, pp. 68-79) precedes the formation of a neoplastic lesion. A neoplastic lesion may evolve clonally to grow into a solid tumor, and develop an increasing capacity for invasion, growth, metastasis, and heterogeneity, especially under conditions in which the neoplastic cells escape the host""s immune surveillance (Roitt, I., Brostoff, J and Kale, D., 1993, Immunology, 3rd ed., Mosby, St. Louis, pps. 17.1-17.12).
Leukemia refers to malignant neoplasms of the blood-forming tissues. Transformation to malignancy typically occurs in a single cell through two or more steps with subsequent proliferation and clonal expansion. In some leukemias, specific chromosomal translocations have been identified with consistent leukemic cell morphology and special clinical features (e.g., translocations of 9 and 22 in chronic myelocytic leukemia, and of 15 and 17 in acute promyelocytic leukemia). Acute leukemias are predominantly undifferentiated cell populations and chronic leukemias more mature cell forms.
Acute leukemias are divided into lymphoblastic (ALL) and non-lymphoblastic (ANLL) types. They may be further subdivided by their morphologic and cytochemical appearance according to the French-American-British (FAB) classification or according to their type and degree of differentiation. The use of specific B- and T-cell and myeloid-antigen monoclonal antibodies are most helpful for classification. ALL is predominantly a childhood disease which is established by laboratory findings and bone marrow examination. ANLL, also known as acute myeloblastic leukemia (AML), occurs at all ages and is the more common acute leukemia among adults; it is the form usually associated with irradiation as a causative agent.
Chronic leukemias are described as being lymphocytic (CLL) or myelocytic (CML). CLL is characterized by the appearance of mature lymphocytes in blood, bone marrow, and lymphoid organs. The hallmark of CLL is sustained, absolute lymphocytosis ( greater than 5,000/xcexcL) and an increase of lymphocytes in the bone marrow. Most CLL patients also have clonal expansion of lymphocytes with B-cell characteristics. CLL is a disease of older persons. In CML, the characteristic feature is the predominance of granulocytic cells of all stages of differentiation in blood, bone marrow, liver, spleen, and other organs. In the symptomatic patient at diagnosis the total WBC count is usually about 200,000/xcexcL, but may reach 1,000,000/xcexcL. CML is relatively easy to diagnose because of the presence of the Philadelphia chromosome.
The very nature of hematopoietic cancer necessitates using systemic chemotherapy as the primary treatment modality. Drugs selected according to sensitivities of specific leukemias are usually given in combination. Radiation therapy may be used as an adjunct to treat local accumulations of leukemic cells. Surgery is rarely indicated as a primary treatment modality, but may be used in managing some complications. Bone marrow transplantation from an HLA-matched sibling is sometimes indicated.
Arsenic has been considered to be both a poison and a drug for a long time in both Western and Chinese medical practices. In the latter part of the nineteenth century, arsenic was used frequently in attempts to treat diseases of the blood in the West. In 1878, it was reported that treatment of a leukemic patient with Fowler""s solution (a solution containing potassium arsenite, valence +5) reduced markedly the count of white blood cells (Cutler and Bradford, Am. J. Med. Sci., January 1878, 81-84). Further interests in the use of Fowler""s solution as a palliative agent to treat chronic myelogenous leukemia (CML) was described by Forkner and Scott in 1931 (J. Am. Med. Assoc., 1931, iii, 97), and later confirmed by Stephens and Lawrence in 1936 (Ann. Intern. Med. 9, 1488-1502). However, while the active chemical ingredient(s) of Fowler""s solution was not determined, its toxicity was well recognized. Fowler""s solution was administered strictly as an oral composition, and was given to leukemic patients as a solution until the level of white blood cells was depressed to an acceptable level or until toxicities (such as skin keratoses and hyperpigmentation) developed, while the patients enjoyed varying periods of remission. In the 1960""s, Fowler""s solution was still used occasionally in attempts to treat CML, however, most patients with CML were treated with other chemotherapeutic agents, such as busulfan, and/or radiation therapy (Monfardini et al., Cancer, 1973, 31:492-501).
Paradoxically, one of the long recognized effects of exposure to arsenic, whether the source is environmental or medicinal, is skin cancer (Hutchinson, 1888, Trans. Path. Soc. Lond., 39:352; Neubauer, 1947, Br. J. Cancer, 1:192). There were even epidemiological data to suggest that the use of Fowler""s solution over long periods could lead to an increased incidence of cancer at internal sites (Cuzick et al., Br. J. Cancer, 1982, 45:904-911; Kaspar et al., J. Am. Med. Assoc., 1984, 252:3407-3408). The carcinogenicity of arsenic has since been demonstrated by the fact that it can induce chromosomal aberration, gene amplification, sister chromatid exchanges and cellular transformation (See e.g., Lee et al., 1988, Science, 241:79-81; and Germolec et al., Toxicol. Applied Pharmacol., 1996, 141:308-318). Because of the known carcinogenic effect of arsenic, its only therapeutic use in human in Western medicine today is in the treatment of tropical diseases, such as African trypanosomiasis, (the organic arsenical, melarsoprol; See Goodman and Gilman""s The Pharmacological Basis of Therapeutics, 9th edition, chapter 66, 1659-1662, 1997).
In traditional chinese medicine, arsenous acid or arsenic trioxide paste has been used to treat tooth marrow diseases, psoriasis, syphilis and rheumatosis (Chen et al., 1995, in Manual of Clinical Drugs, Shanghai, China, Shanghai Institute of Science and Technology, p.830). In 1970""s, arsenic trioxide had been applied experimentally to treat acute promyelocytic leukemia (APL) in China (commented by Mervis, 1996, Science, 273:578). The clinical efficacy of arsenic trioxide has recently been re-investigated in 14 of 15 patients with refractory APL, where the use of an intravenous dose at 10 mg/day for 4-9 weeks was reported to result in complete morphologic remission without associated bone marrow suppression (Shen et al., 1997, Blood, 89:3354-3360). It was also shown that arsenic trioxide induced apoptosis (programmed cell death) in vitro in NB4 cells, an APL cell line, and that apoptosis was apparently associated with down-regulation of the oncogene bcl-2, and intracellular redistribution of the chimeric PML/RARxcex1 protein that are unique to APL cells (Chen et al., 1996, Blood, 88:1052-1061; Andre et al., 1996, Exp. Cell Res. 229:253-260). It has been reported that the biological activity of arsenic is due to the ability of arsenic to direct the nucleoplasmic fraction of PML to nuclear bodies for degradation (Zhu et al., 1997, Proc. Natl. Acad. Sci., 94:3978-3983).
Although arsenic is well known to be both a poison and a carcinogenic agent, there have been many reports concerning the use of arsenic in medical treatment. Further, from the above discussion, it should be clear that there are many different types of leukemias, each of which requires a unique treatment protocol that is modified according to the presence of factors predicting for a risk of treatment failure. Thus, the development of a broad spectrum anti-leukemia agent that can be used alone or in combination with other existing drugs is extremely desirable.
Despite the conflicting reports in the art concerning benefits and risks of the administration of arsenic to patients, applicants have discovered that arsenic trioxide and the organic arsenical, melarsoprol, have broad applicability in the treatment of various types of leukemias, lymphomas, and solid tumors.
The invention described herein encompasses a method of treating leukemia, lymphoma or solid tumors comprising the administration of a therapeutically effective and non-lethal amount of arsenic trioxide or melarsoprol to a human in need of such therapy. The invention, as mentioned above also encompasses the use of combination therapy to treat leukemia, especially leukemias which are refractory to other forms of treatment.
The invention also encompasses a method for the manufacture of pharmaceutical compositions comprising arsenic trioxide.
In accordance with the present invention, arsenic trioxide or melarsoprol compounds can be used alone or in combination with other known therapeutic agents (including chemotherapeutics, radioprotectants and radiotherapeutics) or techniques to either improve the quality of life of the patient, or to treat leukemia, lymphoma or solid tumor. The arsenic compounds can be used before, during or after the administration of one or more known chemotherapeutic agents, including antitumor agents. In addition, the arsenic compounds can be used before, during or after radiation treatment.
The pharmaceutical compositions of the invention are sterile solutions suitable for intravenous injection or infusion. In another embodiment the invention encompasses a composition suitable for oral delivery; comprising arsenic trioxide or melarsoprol and a pharmaceutically acceptable excipient or carrier. In another embodiment, the invention also includes compositions suitable for topical or transdermal delivery, including but not limited to iontophoretic methods. Specific therapeutic regimens, pharmaceutical compositions, and kits are also provided by the invention.
Particular compositions of the invention and their uses are described in the sections and subsections which follow.
Methods and compositions for the treatment of leukemia, lymphoma or solid tumors are described herein. This invention provides a method of treating acute or chronic leukemia, lymphoma, or solid tumors in a human which comprises administering to a human in need of such therapy a therapeutically effective and non-lethal amount of one or more arsenic compounds, such as arsenic trioxide or melarsoprol.
The invention also includes a method of treating leukemia in a human who has become refractory to other forms of treatment which comprises administering to a human arsenic trioxide or melarsoprol in combination with another chemotherapeutic agent, e.g., all-trans retinoic acid (ATRA).
The invention also relates to a method for the manufacture of pharmaceutical compositions comprising arsenic trioxide. It is preferred that pharmaceutical compositions of the present invention exhibit reduced toxicity, improved efficacy, improved stability during storage and use, and that the composition has a physiologically acceptable pH.
As used herein, xe2x80x9carsenic compoundxe2x80x9d refers to a pharmaceutically acceptable form of arsenic trioxide (As2O3) or melarsoprol. Melarsoprol is an organic arsenic compound which can be synthesized by complexing melarsen oxide with dimercaprol or commercially purchased (Arsobal(copyright) by Rhone Poulenc Rorer, Collegeville, Pa.). Since the non-pharmaceutically formulated raw materials of the invention are well known, they can be prepared from well-known chemical techniques in the art. (See for example, Kirk-Othmer, Encyclopedia of Chemical Technology 4th ed. volume 3 pps. 633-655 John Wiley and Sons).
As used herein the terms xe2x80x9ca therapeutic agentxe2x80x9d, xe2x80x9ctherapeutic regimenxe2x80x9d, xe2x80x9cradioprotectantxe2x80x9d, xe2x80x9cchemotherapeuticxe2x80x9d mean conventional drugs and drug therapies, including vaccines, for treating cancer, viral infections, and other malignancies, which are known to those skilled in the art. xe2x80x9cRadiotherapeuticxe2x80x9d agents are well known in the art.
In accordance with the present invention, arsenic trioxide or melarsoprol compounds can be used alone or in combination with other known therapeutic agents (including chemotherapeutics, radioprotectants and radiotherapeutics) or techniques to either improve the quality of life of the patient, or to treat leukemia, lymphoma or solid tumor. For example, the arsenic compounds can be used before, during or after the administration of one or more known antitumor agents including but not limited to mustard compounds, nitrogen mustard, chlorambucil, melphalan, cyclophosphamide, 6-mercaptopurine, 6-thioguanine, cytarabine, 5-fluorouracil, floxuridine, methotrexate, vincristine, vinblastine, taxol, etoposide, temiposide, dactinomycin, daunorubicin, doxorubicin, bleomycin, mitomycin, cisplatin, carboplatin, estramustine phosphate, hydroxyurea, BCNU, procarbazine, VM-26, interferons, and all-trans retinoic acid (ATRA), or other retinoids (See, for example, the Physician Desk References 1997). In addition, the arsenic compounds can be used before, during or after radiation treatment.
In a specific embodiment, the arsenic compound of the invention and ATRA can be administered as a mixture. In preferred aspects, the lymphoma, leukemia or solid tumor in the human treated by the combination is refractory to general methods of treatment, or is a relapsed case of leukemia.
Any suitable mode of administration may be used in accordance with the present invention including but not limited to parenteral administration such as intravenous, subcutaneous, intramuscular and intrathecal administration; oral, and intranasal administration, and inhalation. The mode of administration will vary according to. the type of cancer, and the condition of the human.
The pharmaceutical compositions to be used may be in the form of sterile aqueous or organic solutions; colloidal suspensions, caplets, tablets and cachets.
The term xe2x80x9ca method for treating leukemiaxe2x80x9d as used herein means that the disease and the symptoms associated with the disease are alleviated, reduced, cured, or placed in a state of remission. For example, the methods of treatment of the invention can lower the white blood cell count, or reduce lymphocytosis in a human under treatment.
The term xe2x80x9ca method for treating lymphomaxe2x80x9d as used herein means that the disease and the symptoms associated with the disease are alleviated, reduced, cured, or placed in a state of remission.
The term xe2x80x9ca method for treating solid tumorxe2x80x9d as used herein means that the disease and the symptoms associated with the solid tumor are alleviated, reduced, cured, or placed in a state of remission.
In addition, the term xe2x80x9ca method for treating leukemic infiltrationxe2x80x9d means that the infiltration of leukemic cells out of circulation and into other organs and systems and the symptoms associated with such infiltration are alleviated, reduced, cured, or placed in a state of remission.
The term xe2x80x9crefractoryxe2x80x9d when used herein means that the leukemia is generally resistant to treatment or cure.
As used herein, xe2x80x9cpreneoplasticxe2x80x9d cell refers to a cell which is in transition from a normal to a neoplastic form; or cells that fail to differentiate normally; and morphological evidence, increasingly supported by molecular biologic studies, indicates that preneoplasia progresses through multiple steps.
In one embodiment, the invention provides a method for treatment of leukemia in a human comprising the administration of a therapeutically effective and non-lethal amount of arsenic trioxide or melarsoprol to the human. The invention also provides a weight-based dosing regimen, not heretofore disclosed, that maximizes the safety in humans of these otherwise highly toxic compounds.
Arsenic trioxide (As2O3) inhibits growth and induce apoptosis in NB4 acute promyelocytic leukemic cells. Acute promyelocytic leukemia (APL) is associated with the t(15;17) translocation, which generates a PML/RARxcex1 fusion protein between PML, a growth suppressor localized on nuclear matrix-associated bodies, and RARxcex1, a nuclear receptor for retinoic acid (RA). PML/RARxcex1 was proposed to block myeloid differentiation through inhibition of nuclear receptor response, as does a dominant negative RARxcex1 mutant. In addition, in APL cells, PML/RARxcex1 displaces PML and other nuclear body (NB) antigens onto nuclear microspeckles, likely resulting in the loss of PML and/or NB functions. It has been suggested that high concentrations of arsenic trioxide promote apoptosis, whereas low concentrations induce partial differentiation in NB4 cells as well as cells derived from APL patients. It was postulated that As2O3 works through its ability to specifically cause PML-RARxcex1 in APL cells to be relocalized to nuclear bodies for degradation (Zhu et al., 1997, Proc. Natl. Acad. Sci. USA, 94:3978-3983). However, these findings tend to limit the use of arsenic trioxide to a subset of leukemias. See Konig et al., 1997, Blood, 90:562-570.
Unexpectedly, the inventors have discovered that both As2O3 and melarsoprol are able to inhibit cell growth, and induce apoptosis in various myeloid leukemia cell lines in a PML and PML-RARxcex1 independent manner. Thus, the inventors have discovered that, contrary to the earlier findings, arsenic trioxide and melarsoprol are both effective against a broad range of leukemias regardless of the underlying molecular mechanism that causes the neoplasia. Working examples of the effect of arsenic compounds on a number of leukemic cell lines are provided in Sections 5.1 and 5.2.
Accordingly, the arsenic compounds of the present invention can be used against a variety of leukemias, including but not limited to:
Acute lymphoblastic leukemia (ALL)
Acute lymphoblastic B-cell leukemia
Acute lymphoblastic T-cell leukemia
Acute myeloblastic leukemia (AML)
Acute promyelocytic leukemia (APL)
Acute monoblastic leukemia
Acute erythroleukemic leukemia
Acute megakaryoblastic leukemia
Acute myelomonocytic leukemia
Acute undifferentiated leukemia
Chronic myelocytic leukemia (CML)
Chronic lymphocytic leukemia (CLL)
The skilled artisan will recognize that other leukemias may be treated in accordance with the present invention.
In another embodiment, the invention provides a method for treatment of lymphoma in a human comprising the administration of a therapeutically effective and non-lethal amount of arsenic trioxide or melarsoprol to the human. Lymphoma that can be treated by the methods of the invention include but are not limited to high grade lymphoma, intermediate grade lymphoma, low grade lymphoma, and the various subclassifications.
In yet another embodiment, the invention provides a method for treatment of solid tumors, including metastasises, in humans comprising the administration of a therapeutically effective and non-lethal amount of arsenic trioxide or melarsoprol to the human. Solid tumors that can be treated by the methods of the invention include but are not limited to: cancer of the digestive tract, oesophagus, liver, stomach, and colon; skin; brain; bone; breast; lung; and soft tissues, including but not limited to various sarcomas, and preferably prostate cancer.
In various embodiments, the leukemic or tumor cells are infiltrating other organs and systems in a human, for example, the central nervous system. The methods of the invention are also applicable to reduce the number of preneoplastic cells in a human in which there is an abnormal increase in the number of preneoplastic cells.
In a specific embodiment, the invention provides a method of treatment of acute promyelolytic leukemia (APL) in a human comprising the administration of a therapeutically effective and non-lethal amount of melarsoprol to the human. The inventors discovered, as described in Section 5.2, that concentrations of melarsoprol that are cytotoxic in vitro can readily be achieved in vivo.
In one specific embodiment, the invention provides a method of treatment of chronic myelogenous leukemia (CML) in a human comprising the administration of a therapeutically effective and non-lethal amount of arsenic trioxide to the human. The inventors discovered, as described in Section 5.3, that arsenic trioxide can also induce apoptosis in a CML cell line. The therapeutic benefits of the pharmaceutical compositions of the invention comprising arsenic trioxide is far superior to that of potassium arsenite, commonly formulated as Fowler""s solution.
In yet another specific embodiment, the invention provides a method of treatment of acute promyelocytic leukemia (APL) in a human, in which the APL is associated with a translocation of the RARxcex1 locus on chromosome 17 to chromosome 11, comprising the administration of a therapeutically effective amount of arsenic trioxide or melarsoprol to the human. In the majority of APL cases, RARxcex1 on chromosome 17 translocates and fuses with the PML gene located on chromosome 15, i.e., t(15;17). In a few cases RARA translocates to chromosome 11 where it fuses to the PLZF gene. Patients harboring the t(15;17) are uniquely sensitive to treatment with all-trans retinoic acid (ATRA), yielding complete remission rates of 75% to 95%. APL associated with the t(11;17) (PLZF-RARxcex1) shows a distinctly worse prognosis with poor response to chemotherapy and little or no response to treatment with ATRA, thus defining a new APL syndrome. The present invention provides that arsenic trioxide or melarsoprol can be used to treat such cases of APL. Transgenic animal models of APL associated with t(15;17) and t(11;17) for testing the therapeutic benefits and dosages of arsenic compounds of the invention are described in Section 5.4 hereinbelow.
Humans having leukemia are sometimes refractory to conventional methods of treatment by reason of having undergone anti-leukemic therapy (e.g., chemotherapy). Thus, the invention provides a method of treatment of leukemia in a human who is not responding to conventional therapy comprising the administration of a therapeutically effective and non-lethal amount of a combination of arsenic compound and another chemotherapeutic agent, such as but not limited to, all-trans retinoic acid (ATRA) or other retinoids, to the human. The arsenic compound can either be arsenic trioxide or melarsoprol or a pharmaceutically acceptable salt thereof. The invention also encompasses the treatment of retinoid-resistant patients with an arsenic compound.
In specific embodiments, the arsenic compound of the invention and the chemotherapeutic agent can be administered either as a mixture or sequentially. When administered sequentially, the arsenic compound may be administered before or after the chemotherapeutic agent, so long as the first administered agent is still providing antileukemic activity in the human when the second agent is administered. Any of the modes of administration described herein may be used to deliver the combination. In preferred aspects, the leukemia in the human treated by the combination is refractory to general methods of treatment, or is a relapsed case of leukemia.
The arsenic compounds of the invention may be formulated into sterile pharmaceutical preparations for administration to humans for treatment of leukemias, lymphomas and solid tumors. Compositions comprising a compound of the invention formulated in a compatible pharmaceutical carrier may be prepared, packaged, labelled for treatment of and used for the treatment of the indicated leukemia, lymphoma, or solid tumor.
In one aspect, the invention provides a method for the manufacture of a pharmaceutical composition comprising a therapeutic effective and non-lethal amount of arsenic trioxide (AS2O3). Arsenic trioxide (raw material) is a solid inorganic compound that is commercially available in a very pure form. However, it is difficult to dissolve As2O3 in aqueous solution. Further, the inventors are unaware of any published teachings on how to formulate As2O3 as a pharmaceutical composition suitable for injection directly into a human. Arsenic is present in solution in the +5 valence state (pentavalent) or the +3 valence state (trivalent). For example, potassium arsenite (KASO2; which is present in Fowler""s solution) and salts of arsenious acid contain pentavalent arsenic. It is known that one form of arsenic is more toxic than the other. (Goodman and Gilman""s The Pharmacological Basis of Therapeutics, 9th edition, chapter 66, 1660, 1997). A fresh solution of arsenic trioxide containing arsenic in the trivalent state will be gradually oxidized to pentavalent state if exposed to air for a prolonged period, and as a result of the accumulation of pentavalent arsenic, the relative toxicity of a solution of As2O3 will change over time. (Id.) Furthermore, it is observed that the total amount of arsenic in solution decreases over time. This loss of material is caused by the progressive conversion of arsenic in the solution into arsine (AsH3) which is a gaseous compound at room temperature. This is particularly problematic in pharmaceutical applications if the concentration of an active ingredient in the injected material cannot be controlled. It is also undesirable to allow arsine to escape from the solution into the atmosphere because arsine is also toxic.
The inventors have experimented and successfully developed a method for formulating arsenic trioxide which overcomes the above-described problems of solubility and stability. The method comprises solubilizing solid high purity As2O3 in an aqueous solution at high pH, such as pH greater than 12. For example, a 5 M solution of sodium hydroxide may be used. To aid solubilization and obtain a clear and homogenous solution, mechanical stirring and/or gentle heating may be applied. A solution of As2O3 can also be obtained by dissolving the solid compound overnight. Typically, a solution of 1 M As2O3 is obtained by this method. However, this solution is too basic to be useful as a pharmaceutical composition.
To adjust the pH of the As2O3 solution, the solution is first diluted in water, for example, to a concentration of about 1 mg/mL, pH 12. The As2O3 solution is then back-titrated with acid, such as, hydrochloric acid (1 M to 5 M HCl), with constant stirring until the pH is about 8.0 to 8.5. Highly concentrated HCl is not suitable as it causes precipitation to occur in the As2O3 solution. The partially neutralized As2O3 solution may then be sterilized for example, by filtration (e.g., through a 0.22 xcexcm filter), and stored in sterile vials.
To make a pharmaceutical composition that can be directly injected into a subject, the composition must be sterile, standard techniques known to the skilled artisan for sterilization can be used. See, e.g., Remington""s Pharmaceutical Science, the pH of the partially neutralized As2O3 solution may be further adjusted to near physiological pH by dilution (10-100 fold) with a pharmaceutical carrier, such as a 5% dextrose solution. For example, 10 mL of a partially neutralized As2O3 solution can be added to 500 mL of a 5% dextrose solution to yield a final pH of about 6.5 to 7.5. The method of the invention reduces the oxidation of arsenic in solution. Pharmaceutical compositions containing arsenic trioxide manufactured by the method of the invention show improved stability and long shelf life.
According to the invention, the arsenic compounds and their physiologically acceptable solvates may be formulated for oral or parenteral administration.
For oral administration, the pharmaceutical preparation may be in liquid form, for example, solutions, syrups or suspensions, or may be presented as a drug product for reconstitution with water or other suitable vehicle before use. Such liquid preparations may be prepared by conventional means with pharmaceutically acceptable additives such as suspending agents (e.g., sorbitol syrup, cellulose derivatives or hydrogenated edible fats); emulsifying agents (e.g., lecithin or acacia); non-aqueous vehicles (e.g., almond oil, oily esters, or fractionated vegetable oils); and preservatives (e.g., methyl or propyl-p-hydroxybenzoates or sorbic acid). The pharmaceutical compositions may take the form of, for example, tablets or capsules prepared by conventional means with pharmaceutically acceptable excipients such as binding agents (e.g., pregelatinized maize starch, polyvinyl pyrrolidone or hydroxypropyl methylcellulose); fillers (e.g., lactose, microcrystalline cellulose or calcium hydrogen phosphate); lubricants (e.g., magnesium stearate, talc or silica); disintegrants (e.g., potato starch or sodium starch glycolate); or wetting agents (e.g., sodium lauryl sulphate). The tablets may be coated by methods well-known in the art.
For administration by inhalation, the compounds for use according to the present invention are conveniently delivered in the form of an aerosol spray presentation from pressurized packs or a nebulizer, with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol the dosage unit may be determined by providing a valve to deliver a metered amount. Capsules and cartridges of, e.g., gelatin for use in an inhaler or insufflator may be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.
The compounds may be formulated for parenteral administration by injection, e.g., by bolus injection or is continuous infusion. Formulations for injection may be presented in unit dosage form, e.g., in ampules or in multi-dose containers, with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing and/or dispersing agents. Alternatively, the active ingredient may be in powder form for constitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use.
The invention also provides kits for carrying out the therapeutic regimens of the invention. Such kits comprise in one or more containers therapeutically effective amounts of the arsenic compounds in pharmaceutically acceptable form. The arsenic compound in a vial of a kit of the invention may be in the form of a pharmaceutically acceptable solution, e.g., in combination with sterile saline, dextrose solution, or buffered solution, or other pharmaceutically acceptable sterile fluid. Alternatively, the complex may be lyophilized or desiccated; in this instance, the kit optionally further comprises in a container a pharmaceutically acceptable solution (e.g., saline, dextrose solution, etc.), preferably sterile, to reconstitute the complex to form a solution for injection purposes.
In another embodiment, a kit of the invention further comprises a needle or syringe, preferably packaged in sterile form, for injecting the complex, and/or a packaged alcohol pad. Instructions are optionally included for administration of arsenic compounds by a clinician or by the patient.
The magnitude of a therapeutic dose of an arsenic compound in the acute or chronic management of leukemia will vary with the severity of the condition to be treated and the route of administration. The dose, and perhaps dose frequency, will also vary according to the age, body weight, condition and response of the individual patient. In general, the daily dose ranges of arsenic trioxide for the conditions described herein are generally from about 0.05 to about 5 mg per kg body weight administered in divided doses administered parenterally or orally or topically. A preferred total daily dose is from about 2.5 to about 40 mg of arsenic trioxide. Preferably the arsenic trioxide formulation of the invention is given daily for a maximum of 60 days, or until remission, followed by two to ten additional cycles, each lasting about 25 days in duration. For example, depending on the body weight of a patient with acute promyelocytic leukemia, a daily dose of arsenic trioxide greater than or less than 10 mg can be administered. Alternatively, following the weight-based dosing regimen, a therapeutic effect can be obtained with a daily dose of arsenic trioxide less than 10 mg.
For treatment of solid tumor, a preferred dosing regimen involves intravenous infusion of about 0.1 to about 5 mg per kg body weight per day for 5 days. This five-day treatment protocol is repeated once per month until the tumor growth tumor is inhibited or when the tumor shows signs of regression.
As for melarsoprol, the total daily dose ranges for the conditions described herein are generally from about 0.1 to about 5 mg/kg body weight administered in divided doses administered parenterally or orally or topically. A preferred total daily dose is from about 0.5 to about 4 mg melarsoprol per kg body weight.
The effect of the therapy with arsenic trioxide or melarsoprol on development and progression of cancer can be monitored by any methods known in the art, including but not limited to determining: levels of tumor specific antigens and putative biomarkers, e.g., carcinoembryonic antigens (CEA), alpha-fetoprotein; and changes in morphology and/or size using computed tomographic scan and/or sonogram.
Desirable blood levels may be maintained by a continuous infusion of an arsenic compound as ascertained by plasma levels. It should be noted that the attending physician would know how to and when to terminate, interrupt or adjust therapy to lower dosage due to toxicity, or bone marrow, liver or kidney dysfunctions. Conversely, the attending physician would also know how to and when to adjust treatment to higher levels if the clinical response is not adequate (precluding toxic side effects).
Again, any suitable route of administration may be employed for providing the patient with an effective dosage of an arsenic compound. For example, oral, transdermal, iontophoretic, parenteral (subcutaneous, intramuscular, intrathecal and the like) may be employed. Dosage forms include tablets, troches, cachet, dispersions, suspensions, solutions, capsules, patches, and the like. (See, Remington""s Pharmaceutical Sciences.)
The pharmaceutical compositions of the present invention comprise an arsenic compound as the active ingredient, pharmaceutically acceptable salt thereof, and may also contain a pharmaceutically acceptable carrier, and optionally, other therapeutic ingredients, for example all trans retinoic acid. The term xe2x80x9cpharmaceutically acceptable saltsxe2x80x9d refers to salts prepared from pharmaceutically acceptable non-toxic acids and bases, including inorganic and organic acids and bases.
The pharmaceutical compositions include compositions suitable for oral, mucosal routes, transdermal, iontophoretic, parenteral (including subcutaneous, intramuscular, intrathecal and intravenous), although the most suitable route in any given case will depend on the nature and severity of the condition being treated.
In the case where an intravenous injection or infusion composition is employed, a suitable dosage range for use is, e.g., from about one to about 40 mg arsenic trioxide total daily; about 0.001 to about 10 mg arsenic trioxide per kg body weight total daily, or about 0.1 to about 10 mg melarsoprol per kg body weight total daily.
In addition, the arsenic carrier could be delivered via charged and uncharged matrices used as drug delivery devices such as cellulose acetate membranes, also through targeted delivery systems such as fusogenic liposomes attached to antibodies or specific antigens.
In practical use, an arsenic compound can be combined as the active ingredient in intimate admixture with a pharmaceutical carrier according to conventional pharmaceutical compounding techniques. The carrier may take a wide variety of forms depending on the form of preparation desired for administration, e.g., oral or parenteral (including tablets, capsules, powders, intravenous injections or infusions). In preparing the compositions for oral dosage form any of the usual pharmaceutical media may be employed, e.g., water, glycols, oils, alcohols, flavoring agents, preservatives, coloring agents, and the like; in the case of oral liquid preparations, e.g., suspensions, solutions, elixirs, liposomes and aerosols; starches, sugars, micro-crystalline cellulose, diluents, granulating agents, lubricants, binders, disintegrating agents, and the like in the case of oral solid preparations e.g., powders, capsules, and tablets. In preparing the compositions for parenteral dosage form, such as intravenous injection or infusion, similar pharmaceutical media may be employed, e.g., water, glycols, oils, buffers, sugar, preservatives and the like know to those skilled in the art. Examples of such parenteral compositions include, but are not limited to Dextrose 5% w/v, normal saline or other solutions. The total dose of the arsenic compound may be administered in a vial of intravenous fluid, e.g., ranging from about 2 ml to about 2000 ml. The volume of dilution fluid will vary according to the total dose administered. For example, arsenic trioxide supplied as a 10 ml aqueous solution at 1 mg/ml concentration is diluted in 10 to 500 ml of 5% dextrose solution, and used for intravenous infusion over a period of time ranging from about ten minutes to about four hours.
An exemplary course of treatment of a patient with leukemia, lymphoma, or solid cancer can involve daily administration by intravenous infusion of arsenic trioxide in an aqueous solution at a daily dose of about 0.01 to 1 mg arsenic trioxide per kg of body weight of the patient. Preferably, about 0.15 mg arsenic trioxide per kg body weight per day is used. The course of treatment may continue until bone marrow remission is observed or when side effects are becoming serious. The course of treatment may be repeated for up to ten times over approximately 10 months with a break of about 3 to 6 weeks in between courses. The post-remission course of treatment involves infusion of arsenic trioxide at a daily dose of about 0.15 mg per kg of body weight of the patient on a daily or weekdays-only basis for a cumulative total of 25 days.